GEOPRIV H. Schulzrinne
Internet-Draft Columbia U.
Expires: August 8, 2004 February 8, 2004
DHCP Option for Civil Addressesdraft-ietf-geopriv-dhcp-civil-00
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Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document specifies a Dynamic Host Configuration Protocol (DHCP)
option for the civil (country, street and community) location of the
client.
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Internet-Draft DHCP Civil February 20042. Introduction
Many end system services can benefit by knowing the approximate
location of the end device. In particular, IP telephony devices need
to know their location to contact the appropriate emergency response
agency and to be found by emergency responders.
There are two common ways to identify the location of an object,
either through geospatial coordinates or by so-called civil
coordinates. Geospatial coordinates indicate longitude, latitude and
altitude, while civil coordinates indicate a street address.
A related draft [6] describes a DHCP [2] option for conveying
geospatial information to a device. This draft describes how DHCP
can be used to convey the civil location to devices. Both can be
used simultaneously, increasing the chance to deliver accurate and
timely location information to emergency responders.
End systems that obtain location information via the mechanism
described here then use other protocol mechanisms to communicate this
information to the emergency call center.
Civil information is useful since it often provides additional,
human-usable information particularly within buildings. Also,
compared to geospatial information, it is readily obtained for most
occupied structures and can often be interpreted even if incomplete.
For example, for many large university or corporate campuses,
geocoding information to building and room granularity may not be
readily available.
Unlike geospatial information, the format for civil information
differs from country to country. Thus, this draft establishes an
IANA registry for civil location data fields. The initial set of
data fields is derived from standards published by the United States
National Emergency Numbering Association (NENA) [8]. It is
anticipated that other countries can reuse many of the data elements.
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Internet-Draft DHCP Civil February 2004
| 25 | | type of place | |
| | | | |
| 26 | | floor | |
| | | | |
| 27 | | room number | |
+----------------+----------------+----------------+----------------+
The CA types labeled in the second column correspond to items from
the NENA "Recommended Formats & Protocols For ALI Data Exchange, ALI
Response & GIS Mapping" [8], but are applicable to most countries.
The "NENA" column refers to the data dictionary name in Exhibit 18 of
[8].
The NAM object is used to aid user location ("Joe Miller" "Alice's
Dry Cleaning"). It does not identify the person using a
communications device, but rather the person or organization
associated with the address.
For POD and PRD, in English-speaking countries, the abbreviations N,
E, S, W, and NE, NW, SE, SW should be used.
STS designates a street suffix. In the United States (US), the
abbreviations recommended by the United States Postal Service
Publication 28 [7], Appendix C, SHOULD be used.
The "type of place" item indicates whether the location is a 'home',
'office' or 'public', using text strings. Additional text strings
can be registered with IANA and correspond to the "placetype" element
in [9].
The "privacy" object can have the string values:
public: Others may be able to see or hear the communications.
private: Inappropriate individuals are not likely to see or hear the
communications.
quiet: The location is a place such as a library, restaurant,
place-of-worship, or theater that discourages noise, conversation
and other distractions.
Additional string values can be registered with IANA using the
registry established in [9].
The DHCP long-options mechanism described in RFC 3396 [3] MUST be
used if the civil address option exceeds the maximum DHCP option size
of 255 octets.
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Internet-Draft DHCP Civil February 20045. Security Considerations
The information in this option may be used for a variety of tasks. In
some cases, integrity of the information may be of great importance.
In such cases, DHCP authentication in RFC3118 [4] SHOULD be used to
protect the integrity of the DHCP options.
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